Rainwater laws / California
Is it legal to collect rainwater in California?
Checked at California's own statutes and agencies, November 2026. Not legal advice.
Allowed; plumbing rules for indoor use
Yes. California's Rainwater Capture Act says using rain from your rooftop needs no water right permit. Systems that plumb into the house follow the plumbing code.
What the rules say
- Water Code 10574: "Use of rainwater collected from rooftops does not require a water right permit pursuant to Section 1201."
- The California Plumbing Code sets water quality for indoor uses where there's no local rule. Irrigation systems under 360 gallons have no quality minimum.
Tax breaks and help
Adding a rain capture system doesn't count as new construction for property tax (Revenue and Taxation Code 74.8), through January 1, 2029.
Before you buy a big tank
State law is only one layer. Cities and counties can set their own rules, especially for tanks plumbed into the house, and an HOA can limit where a barrel sits. Drinking rainwater needs treatment everywhere. For a barrel or two on a downspout for the garden, the state rule above is usually the one that matters.
Where the numbers come from
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